Method of electrical welding



T. E. MURRAY, JR., AND J. B. MURRAY.

METHOD OF ELECTRICAL WELDING.

APPLICATION FILED JAN. 3, I920.

Patented May 11, 1920.

avwawltoz M UNITED STATES PATENT OFFICE.

THOMAS E. MURRAY, JR., AND JOSEPH B. MURRAY, OF BROOKLYN, NEW YORK.

METHOD OF ELECTRICAL WELDING.

Specification of Letters Yatent.

Patented May 11, 1920.

Application filed January 3, 1920. Serial No. 349,185.

To all whom it may concern:

Be it known that we THOMAS E. MUR- RAY, Jr., and JOSEPH B. MURRAY, citizens of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented a certain new and useful Improvement in Methods of Electrical Welding, of which the following is a specification.

As a result of many experiments in electrically welding the registering edges of two hollow objects of sheet metal, we found that said dges,-while the current was acting,

became more or less out of registry, thus changing the contact area at the joint, modifying the heating effect of the current and affecting the perfection of the weld. For some time the cause of this continued obscure, but finally we discovered that the walls of the objects were evidently set into transverse vibration by the alternating current, and so the source of-the trouble having been recognized, the problem reduced itself to finding a way to eliminate the difficulty. This we have now accomplished by the method hereinafter set forth.

When the hollow object-as, for example, the longitudinal half section of a tube-is seated directly in an electrode in which it closely fits,that portion ofv its total vibration amplitude which acts outwardly from the rest position of the half section wall is stopped by the contacting wall of the electrode. But the portion of said vibration amplitudewhich'acts inwardly i's unchecked, so that the contacting walls of the work, being free to move in this direction become relatively displaced, as before, at their abutting edges. After trying many expedients to overcome this, we found the simplest conception the most effective and satisfactory .solution of the problem.

In the accompanying drawing- Figure 1 is an end view of the longitudinal half section of a cylindrical tube seated in c an electrode. Fig. 2 is a similar view, the

half section being rectangular in shape.

Similar letters of reference indicate like In Fig. 1, A is anend view of a semitubular object seated and fitting in the electrode B. If nothing more is done, the outtacting electrode, but the inward vibrationsin the direction of the arrows 1, Fig. 1, will be unchecked. But all that is necessary to stop them is to make the object sufficiently resilient as that when it is placed in the electrode, it will be compressed and so exercise an outward pressure on said electrode. To illustrate: the semi-tubular object may be made, as shown at C, in dotted ilines, Fig. 1, of a'diameter greater than that of the seat in the electrode, so that to introduce it into said seat it must be compressed and to the diameter of object A. Any tendency then of its wall to move inwardly is opposed by its own outwardly act ing resiliency. The extent of inward movement, if unchecked, being easily recognized, for any given example of a class or series of identical objects it is a simple proceeding to give them a dimension suflicient to cause them to exert a counter-balancing or overbalancing force. That done, the edges at the weld remain in registry while the current is on.

We claim:

The method of preventing transverse vibration of the edges of a hollow object of sheet metal during the electrical welding ofsaid edges to the registering edges of a similar object by means of an alternating current, which consists in forming said object with a transverse dimension greater than the corresponding transverse dimension of a recess formed in an electrode, seating said object in said recess, and thereby compressing said object to cause the same to press resiliently against its seat in said electrode; whereby tendency of said object'to inward vibration is met byits own outwardly acting resilienc In testimony whereof wehave afiixed our signatures in presence of two witnesses.

THOMAS E. MURRAY, JR. JOSEPH B. MURRAY.

Witnesses:

GERTRUDE T. PORTER, MAY T. MGGARRY. 

